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[expr.throw] Make wording for throw-expressions more consistent with [expr] CWG2699 #3921

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[expr.throw] Make wording for throw-expressions more consistent with [expr] CWG2699 #3921

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30 changes: 11 additions & 19 deletions source/expressions.tex
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Original file line number Diff line number Diff line change
Expand Up @@ -6584,19 +6584,21 @@
A \grammarterm{throw-expression} is of type \tcode{void}.

\pnum
Evaluating a \grammarterm{throw-expression} with an operand throws an
exception\iref{except.throw}; the type of the exception object is determined by removing
any top-level \grammarterm{cv-qualifier}{s} from the static type of the
operand and adjusting the type
from ``array of \tcode{T}'' or function type \tcode{T}
to ``pointer to \tcode{T}''.
A \grammarterm{throw-expression} with an operand throws an exception\iref{except.throw}.
The array-to-pointer\iref{conv.array} and function-to-pointer\iref{conv.func}
standard conversions are performed on the operand.
The type of the exception object\iref{except.throw} is determined by
removing any top-level cv-qualifiers from the type of the (possibly-converted) operand.
Comment on lines +6588 to +6591
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This is technically a normative change: previously throwing a const char[3] would throw a char* rather than const char*. But the old wording is sufficiently obviously wrong that that seems OK.

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Ah, I see that's #3959. I even managed to pick exactly the same example!


\pnum
\indextext{exception handling!rethrow}%
A
\grammarterm{throw-expression}
\indextext{exception handling!terminate called@\tcode{terminate} called}%
\indextext{\idxcode{terminate}!called}%
A \grammarterm{throw-expression}
with no operand rethrows the currently handled exception\iref{except.handle}.
The exception is reactivated with the existing exception object;
If no exception is currently being handled,
the function \tcode{std::terminate} is called\iref{except.terminate}.
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Suggested change
the function \tcode{std::terminate} is called\iref{except.terminate}.
the function \tcode{std::terminate} is invoked\iref{except.terminate}.

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@zygoloid zygoloid Oct 18, 2020 •
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Generally-speaking, we consider "call" to be syntactic (f(a,b) is a function call) and "invoke" to be semantic (a + b for an overloaded operator+ invokes a function but doesn't involve a function call). This terminology isn't used consistently everywhere, but it seems like a good idea to use the more-precise terminology in wording we're touching anyway.

Otherwise, the exception is reactivated with the existing exception object;
no new exception object is created.
The exception is no longer considered to be caught.
\begin{example}
Expand All @@ -6612,16 +6614,6 @@
\end{codeblock}
\end{example}

\pnum
\indextext{exception handling!rethrow}%
\indextext{exception handling!terminate called@\tcode{terminate} called}%
\indextext{\idxcode{terminate}!called}%
If no exception is presently being handled,
evaluating a
\grammarterm{throw-expression}
with no operand calls
\tcode{std::\brk{}terminate()}\iref{except.terminate}.

\rSec2[expr.ass]{Assignment and compound assignment operators}%
\indextext{expression!assignment and compound assignment}

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